Editor's note: The video above, from January 2019, answers commonly asked questions about measles.

PORTLAND, Ore. — There have been nine cases of measles identified in Clackamas and Multnomah counties since the beginning of July, including two cases confirmed since the Oregon Health Authority last updated their numbers on August 14.

Twenty three people have contracted the measles virus this year in Oregon in three separate outbreaks, the largest annual number in the state since 1991, when the state identified nearly 100 cases of measles.

According to Multnomah County health officials, none of the nine people who contracted the measles virus since July were immunized. All have stayed home while contagious and pose no risk to the public.  

Most of the people diagnosed with measles this year in Oregon have been children, half of them old enough to go to school. They were kept home from classes, sports and social events while they were contagious.

RELATED: US measles count surpasses 25-year-old record

Multnomah County Deputy Health Officer Dr. Jennifer Vines urges families to keep their children safe and make sure they are up-to-date on the measles, mumps, and rubella vaccine.

"Measles is a serious illness, people are miserable for a week and very contagious while sick," Vines said. "Fully vaccinated kids also protect their siblings, friends and teachers."

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Vines said measles can spread through the air after a person with it coughs or sneezes, and the virus can also linger in the air for up to two hours after someone who is infectious has left.

"A measles case in school can be dangerous to unvaccinated pregnant women and medically fragile children and adults," Vines said. If someone at school comes down with measles, students who haven't been vaccinated and are exposed to the virus have to stay out of school for 21 days.

RELATED: Thousands of US kindergartners unvaccinated without waivers

Immunizations are among the safest ways to stop the spread of disease and keep children in school, Vines said. The state requires children who go to daycares and schools to get vaccines to protect against polio, hepatitis, and whooping cough, among other infections.

If you have questions about vaccinations, please contact your primary care physician or attend one of these parent-led free informational community workshops.